Dr. Nathan Jideama, citizen of the US is a minority faculty employed as an assistant professor at Clark Atlanta University. Dr. Jideama earned a Ph.D degree from Atlanta University and completed post doctoral training under Dr. J.F. Kuo at Emory University School of Medicine in 1996. Dr. Jideama's career goal is to develop his research such that it can be used to train minority student. Dr. Jideama's research area is regulation of cardiac functions by protein kinases and phosphotases. His proposed research is described below. Cardiac muscle contraction is regulated by protein kinases (PKC and PKA) through phosphorylation of myofibrillar proteins and protein phosphotase 1 (PP1) through dephosphorylation of these proteins. The overall objective of this proposal is to determine the concerted roles of protein kinase C (PKC) isozymes (alpha,,delta,,epsilon, and zetu), protein kinase A (PKA) and protein phosphatase 1 (PP1) in the regulation of cardiac functions. Phosphorylation, dephosphorylation, activity assay and contractile measurements of myocytes will be used to determine the roles of PKC isozymes, PKA and PP1 in cardiac functions. The effects of phosphorylation and dephosphorylation on Ca2+--stimulated MgATPase activity will be determined. Site-specific phosphorylation patterns of myofibrillar proteins will be evaluated through two- dimensional phosphopeptide mapping. Functional significance of phosphorylation of myofibrils by PKC isozymes and PKA and the dephosphorylation by PP1 will also be determined. Cardiomyocytes contractility will be measured to determine the biochemical and physiological effects of phosphorylation and dephosphorylation of cardiac myofibrils. It is anticipated that data collected from this study will provide new insights in the regulation of heart function by PKC, PKA and PPI. It will also enhance our understanding of the functions of cardiac contractile apparatus.